/**
 * Copyright (c) 2006 George Malamidis, nutrun.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies
 * or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * $Author$
 * $Rev$
 */

package aerie.filter;

import groovy.lang.GroovyClassLoader;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class FilterPool {
    private File dir;
    private Map filters = new HashMap();
    private static GroovyClassLoader groovyClassLoader;
    private static long lastModifiedTime;

    public FilterPool(File dir) {
        this.dir = dir;
        loadFilters();
    }

    public Filter getFilter(String filter) {
        if (lastModifiedTime != dir.lastModified()) loadFilters();
        return ((CachedFilter) filters.get(filter)).getFilter();
    }

    private void loadFilters() {
        lastModifiedTime = dir.lastModified();
        final File[] files = dir.listFiles();
        groovyClassLoader = new GroovyClassLoader(getClass().getClassLoader());
        File file;
        //noinspection ForLoopReplaceableByForEach
        for (int i = 0; i < files.length; i++) {
            file = files[i];
            if (file.getName().endsWith(".groovy")) {
                loadFilterFrom(file);
            }

        }
    }

    private void loadFilterFrom(File file) {
        try {
            final Object filter = groovyClassLoader.parseClass(file).newInstance();
            if (filter instanceof Filter) {
                //noinspection unchecked
                filters.put(filter.getClass().getName(), new CachedFilter((Filter) filter, file));
            }
        } catch (InstantiationException e) {
            throw new RuntimeException("Unable to instantiate Filter [" + file.getName() + "]", e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException("Filter [" + file.getName() + "] not found", e);
        }
    }

    /**
     * For testing only
     * @return the Map containing the Filters
     */
    Map getFilters() {
        return filters;
    }
}
